This invention relates to an internal combustion engine and more particularly to an improved induction and fuel injection system for such engines.
It has been acknowledged that the performance of an internal combustion engine can be significantly improved by employing multiple intake valves. Four valve per cylinder engines are quite common and the advantages of a five valve engine over a four valve engine are now being recognized. Five valve engines employ three intake valves and two exhaust valves per cylinder.
Although the use of three intake valves can significantly increase the performance of an engine, it also can in many ways complicate the construction of the engine. In order to provide a less complicated engine, it has been proposed to employ a Siamese type intake port arrangement for such engines. With such an arrangement, a single intake opening is formed in the side of the cylinder head and this intake opening serves three intake valves through a bifurcated intake passage. In order to permit a more compact engine construction, however, it has been proposed to shift the center of the intake opening relative to the intake ports which it serves. By so staggering the offset of the intake openings, the length of the engine can be decreased.
It is also a practice to employ a single charge former for the multiple intake valves and this adds to the simplicity of the engine. When fuel injection is employed, a single manifold injector will spray fuel into the intake opening for serving each of the intake valves for a given combustion chamber. However, when the intake opening is offset from the center of the valves, then the fuel injector is normally offset in the same direction and will not provide equal fuel distribution to the individual valve seats.
Although it is possible to have the fuel injector disposed at an angle so that its spray will be more centrally of the intake passages and supply all of the valve ports equally, there are disadvantages to employing such angled fuel injectors. One of the main of these disadvantages is that it is difficult to provide a common fuel rail for serving multiple fuel injectors when they are offset.
It is, therefore, a principal object of this invention to provide an improved induction system and fuel injection system for a multiple valve internal combustion engine.
It is a further object of this invention to provide an improved Siamese intake system for serving multiple intake valves of a single cylinder of the engine, permitting offsetting of the opening of the intake passages relative to the intake ports and yet employ a single fuel injector that will supply fuel equally to all of the intake ports.
It is a further object of this invention to provide an improved arrangement for the fuel injectors of an internal combustion engine which permits the fuel injectors to extend parallel to each other so that a common fuel rail may be obtained even though the intake passages may be asymmetric.